1. Field of the Invention
The present invention relates generally to a lateral perforation forming apparatus for a form printing machine. More particularly, the invention relates to an arbitrarily positioned lateral perforation forming apparatus for forming a lateral perforation at an arbitrary position or a selected position in a continuous web paper printed by a form printing machine, depending upon a printed image.
2. Description of the Related Art
Since a form printing machine performs a printing by means of a plate cylinder having a predetermined peripheral length, printing on a continuous web paper repeatedly makes a print per predetermined length in a feeding direction of the continuous web paper, namely makes repeated prints of the same image. Then, when a lateral or cross line perforation aligned in a perpendicular direction to a longitudinal direction of the continuous web paper is formed in a part of the printed image of such repeated prints of the same image, it is typical to perform a formation of the perforation by means of a perforation forming cylinder or a roulette cylinder having the same peripheral length as the plate cylinder in a similar manner to printing. In such conventional apparatus, the perforation formation is inherently performed sequentially and repeatedly for all printed images. Therefore, it has not been possible to form the lateral perforation only for preliminarily selected image.
In addition to the above-mentioned typical prior art, there has been known the conventional lateral perforation forming apparatus which can form a perforation to preliminarily selected printed image. Such perforation forming apparatus have been disclosed in Japanese Patent No. 2559036 and Japanese Unexamined Patent Publication (Kokai) No. Heisei 9-76460.
The former apparatus as disclosed in Japanese Patent No. 2559036 includes a rotary body driving source separately from a paper drive mechanism for feeding a continuous web paper. The disclosed apparatus further comprises a rotary body having a plurality of perforation forming portions performing a formation of lateral perforation in the continuous web paper and inactive portions located between the perforation forming portions and not contacting with the continuous web paper, a perforation forming pattern input portion for inputting a perforation forming pattern to be formed by the perforation forming portion of the rotary body, a detector for detecting a feed position and a feed speed of the continuous web paper fed by the paper drive mechanism, and a control unit, in response to a continuous web paper feed amount signal generated by the detector, adjusting a rotation speed of the rotary body to the same speed as the paper feeding speed when each perforation forming portion of the rotary body performs the formation of perforation for the continuous web paper, and electrically controlling the driving source of the rotary body to adjustably increase and decrease a rotation speed of the rotary body relative to the feed speed of the continuous web paper upon non-forming of perforation where each inactive portion of the rotary body is placed in opposition to a feeding path of the continuous web paper, and whereby adjusting interval of a plurality of perforation forming position of the continuous web paper.
On the other hand, the latter apparatus as disclosed in Japanese Unexamined Patent Application No. Heisei 9-76460 is originally adapted for cutting the continuous web paper at predetermined positions. However, the apparatus is also applicable to a formation of the lateral perforation. The apparatus comprises a cutting cylinder (roulette cylinder), which is disposed on an upstream side of an oscillatory shooter assembly in a web paper traveling path. The cutting cylinder includes a full edge type cutting member (lateral roulette edge) which is protruded from a peripheral surface of the cutting cylinder and which forms the cross line of cuts (lateral perforation) interposed by at least one small uncut portion in the continuous web paper. The cutting cylinder is synchronously rotated with the feeding speed of the continuous web paper for forming the cross line of cuts (lateral perforation) in response to a signal detecting the predetermined feeding length of said continuous web paper. In the construction set forth above, bearing boxes supporting both ends of the cutting cylinder are supported on frames for eccentric rotation relative to a center of the cutting cylinder so that the cutting cylinder is moved toward and away from an impression cylinder (receptacle cylinder) according to eccentric rotation of the bearing box for forming the cross line of cuts (forming lateral perforation) in the continuous web paper upon contacting of the cutting cylinder with the impression cylinder.
The former prior art is so-called a single motor type lateral perforation forming apparatus and encounters the following problem.
The disclosed apparatus performs the formation of lateral perforation by driving a stand-alone lateral perforation forming motor provided independently of the motor for paper feeding, in synchronism with a signal from the control unit. However, due to an inertia load of the lateral roulette cylinder and an impact upon the formation of perforation, the rotation and perforation formation may be performed in a condition where the position of the roulette edge is dislocated from the position synchronized with the signal to cause an error in the perforation forming position in the product.
The foregoing phenomenon becomes more significant at higher speed operation where the inertia load of the lateral roulette cylinder becomes greater. For this reason, in order to facilitate an accurate control of rotation of the lateral roulette cylinder in high speed range, the lateral roulette cylinder having small diameter, e.g. about 80 mm in diameter, inducing smaller inertia load, is employed. However, it causes a problem that the lateral perforation is not formed for a deflecting deformation of the lateral roulette cylinder. In addition, the rotation of the lateral roulette cylinder has to be accurately synchronized with flow of the continuous web paper. Since the rotating drive source is the single motor, a large servo motor (pulse motor) having high torque becomes necessary. Then, a drive control portion for the servo motor having large capacity has to be used to perform the accurate synchronization, to result in high cost.
On the other hand, the latter prior art does not require the roulette position control depending upon motor control which encounters the drawback in the former prior art, but can form perforation at accurate position in mechanical synchronous operation. However, the latter prior art encounters the following problem.
Namely, since the bearing box supporting the lateral roulette cylinder rotates eccentrically relative to the center of the lateral roulette cylinder at every time of formation of lateral perforation, a play should be caused by wearing in a rotary support of the frame rotatably supporting the bearing box through repeated rotating operation, to result in an accident that the lateral perforation is not formed. On the other hand, accurate fitting between the bearing box and the frame is difficult to establish, both the components should be finished for avoiding play, and thermal expansion can be caused in the fitting portion to make the bearing box to difficult to rotate for frequent rotation of the bearing box, to require a large capacity driving source, such as a liquid pressure cylinder, for driving the bearing box to rotate overcoming the resistance increased due to thermal expansion. If the driving source becomes large, response characteristics to a control command is degraded to cause a failure in movement of the roulette cylinder toward and away from the receptacle cylinder.
Therefore, an anti-friction bearing, such as needle bearing, may be used in rotating support portion of the bearing box in the frame. However, cost becomes high. Furthermore, since such anti-friction bearing is not durable against impact load and vibration load to cause play and damage at early timing in the anti-friction bearing.
The present invention has been worked out in view of the drawbacks in the prior art set forth above. Therefore, it is an object of the present invention to provide an arbitrarily positioned lateral perforation forming apparatus which can form lateral perforation in an arbitrary position or a selected position of a continuous web paper with small control amount to permit simplification of a control system, and can accurately form lateral perforation at the arbitrary position or the selected position.
In order to accomplish the above-mentioned objects, a arbitrarily positioned lateral perforation forming apparatus, according to the present invention, comprises:
a lateral roulette cylinder projecting a lateral roulette edge on its outer periphery, arranged on one side of a continuous web paper, and rotating in a traveling direction of the continuous web paper;
a receptacle cylinder projecting an edge receptacle portion opposing to the lateral roulette edge of the lateral roulette cylinder, on its outer periphery, arranged on the other side of the continuous web paper, rotating in the traveling direction of the continuous web paper, and forming a lateral perforation in the continuous web paper when the edge receptacle portion is in opposition to the roulette edge;
a drive system for rotating the lateral roulette cylinder and the receptacle cylinder in synchronism with traveling of the continuous web paper;
a first differential mechanism disposed in an element connected to one of the lateral roulette cylinder and the receptacle cylinder in the drive system, causing difference in rotational phases of the lateral roulette cylinder and the receptacle cylinder by varying rotation of a differential shaft thereof for selectively placing the edge receptacle portion at a position opposing to the roulette edge and a position circumferentially offsetting from the roulette edge; and
a first control unit for controlling rotation of the differential shaft of the first differential mechanism.
In addition to the foregoing construction, it is preferred that the arbitrarily positioned lateral perforation forming apparatus further comprises a second differential mechanism disposed in an element commonly connected to the lateral roulette cylinder and the receptacle cylinder in the drive system, and varying a position to be formed with the lateral perforation in the continuous web paper by making rotations of the lateral roulette cylinder and the receptacle cylinder synchronous with traveling of the continuous web paper by varying rotation of a differential shaft thereof; and.
a second control unit for controlling rotation of the differential shaft of the second differential mechanism.
In addition to the foregoing construction, it is preferred that the arbitrarily positioned lateral perforation forming apparatus further comprises:
a mark sensor reading a mark printed on the continuous web paper and inputting a mark read signal to the first control unit,
the first control unit is responsive to the mark read signal for driving the first differential mechanism to perform a formation of lateral perforation.
Furthermore, the first differential mechanism may be disposed in the element connected to the receptacle cylinder of the drive system or in the element connected to the roulette cylinder in the drive system.
With the construction set forth above, the lateral roulette cylinder and the receptacle cylinder are driven to rotate along the traveling direction of the continuous web paper by the drive system. Then, at this time, by rotating the differential shaft of the first differential mechanism, the rotational phase of one of the lateral roulette cylinder and the receptacle cylinder is shifted relative to the rotational phase of the other.
By causing difference in the rotational phases, when the lateral roulette edge of the lateral roulette cylinder is placed in opposition to the edge receptacle portion projecting on the receptacle cylinder, the lateral perforation can be formed in the continuous web paper traveling therebetween. The formation of the lateral perforation can be arbitrarily performed by controlling the first differential mechanism via the first control unit. Furthermore, by only shifting the rotational phase of one of the lateral roulette cylinder and the receptacle cylinder relative to the rotational phase of the other, one of the cylinders can be selectively placed at the active position where the lateral perforation is formed and inactive position where the lateral perforation is not formed. Thus, the lateral perforation can be arbitrarily formed with small control amount. Accordingly, the control system can be simplified, and the lateral perforation can be formed at arbitrary position with high precision.
Also, by rotation the differential shaft of the second differential mechanism via the second control unit, rotation of the lateral roulette cylinder and the receptacle cylinder can be synchronous with traveling of the continuous web paper. By this, the position to be formed with the lateral perforation can be arbitrarily varied in the longitudinal direction (traveling direction) of the continuous web paper.
Further, the actuation of the first differential mechanism is performed by reading the mark by the mark sensor and on the basis of the read signal. By this, only on the portion of the continuous web paper where the mark is printed, the lateral perforation can be formed. For example, the lateral perforation can be formed at a predetermined position of a sheet with the mark which is preliminarily printed on the continuous web paper. By this the lateral perforation can be selectively formed at the portion of the preliminarily selected image.
The present invention will be understood more fully from the detailed description given herebelow and from the accompanying drawings of the preferred embodiment of the present invention, which, however, should not be taken to be limitative to the invention, but are for explanation and understanding only.